This invention relates generally to refrigeration and, more particularly, to the generation of refrigeration using refrigerant fluids which have a lesser environmental impact than do conventional refrigerant fluids.
Conventional refrigerants, such as chlorofluorocarbons, are being phased out because of their high environmental impact and are being replaced by other more environmentally friendly refrigerant fluids. However, in general, a refrigeration cycle or circuit using such replacement refrigerant fluids consumes significantly more power than one using conventional refrigerants on an equivalent refrigeration basis. This markedly reduces the advantages of using such replacement refrigerants.
Accordingly it is an object of this invention to provide a method for providing refrigeration which can more effectively employ environmentally friendly refrigerant fluids to generate the refrigeration.
The above and other objects, which will become apparent to those skilled in the art upon a reading of this disclosure, are attained by the present invention which is:
A method for providing refrigeration to a refrigeration load comprising:
(A) providing warm temperature supercritical pressure refrigerant fluid and compressing the warm temperature supercritical pressure refrigerant fluid to be at a higher supercritical pressure;
(B) cooling the higher supercritical pressure refrigerant fluid and expanding the cooled higher supercritical pressure refrigerant fluid to produce cold temperature supercritical pressure refrigerant fluid; and
(C) warming the cold temperature supercritical pressure refrigerant fluid by indirect heat exchange with said cooling higher supercritical pressure refrigerant fluid and by indirect heat exchange with a refrigeration load to produce said warm temperature supercritical pressure refrigerant fluid.
As used herein the term xe2x80x9ccritical pressurexe2x80x9d means the pressure of a fluid at which the liquid and vapor phases can no longer be differentiated. A supercritical pressure fluid is a fluid which is at a pressure which is greater than its critical pressure.
As used herein the term xe2x80x9ccritical temperaturexe2x80x9d means the temperature of a fluid above which a distinct liquid phase can no longer be formed regardless of pressure.
As used herein the term xe2x80x9cexpansionxe2x80x9d means to effect a reduction in pressure.
As used herein the term xe2x80x9cexpansion devicexe2x80x9d means apparatus for effecting expansion of a fluid.
As used herein the term xe2x80x9ccompressorxe2x80x9d means apparatus for effecting compression of a fluid.
As used herein the term xe2x80x9crefrigerationxe2x80x9d means the capability to reject heat from a subambient temperature system.
As used herein the term xe2x80x9crefrigerant fluidxe2x80x9d means a fluid in a refrigeration process which undergoes changes in temperature, pressure and possibly phase to absorb heat at a lower temperature and reject it at a higher temperature.
As used herein the term xe2x80x9cindirect heat exchangexe2x80x9d means the bringing of fluids into heat exchange relation without any physical contact or intermixing of the fluids with each other.
As used herein the term xe2x80x9crefrigeration loadxe2x80x9d means a fluid or object that requires a reduction in energy, or removal or heat, to lower its temperature or to keep its temperature from rising.